Assessment of Myofascial Trigger Points via Imaging: A Systematic Review

ABSTRACT

This study systematically reviewed the published literature on the objective characterization of myofascial pain syndrome and myofascial trigger points using imaging methods. PubMed, Embase, Ovid, and the Cochrane Library databases were used, whereas citation searching was conducted in Scopus. Citations were restricted to those published in English and in peer-reviewed journals between 2000 and 2021. Of 1762 abstracts screened, 69 articles underwent full-text review, and 33 were included. Imaging data assessing myofascial trigger points or myofascial pain syndrome were extracted, and important qualitative and quantitative information on general study methodologies, study populations, sample sizes, and myofascial trigger point/myofascial pain syndrome evaluation were tabulated. Methodological quality of eligible studies was assessed based on the Quality Assessment of Diagnostic Accuracy Studies criteria. Biomechanical properties and blood flow of active and latent myofascial trigger points assessed via imaging were found to be quantifiably distinct from those of healthy tissue. Although these studies show promise, more studies are needed. Future studies should focus on assessing diagnostic test accuracy and testing the reproducibility of results to establish the best performing methods. Increasing methodological consistency would further motivate implementing imaging methods in larger clinical studies. Considering the evidence on efficacy, cost, ease of use and time constraints, ultrasound-based methods are currently the imaging modalities of choice for myofascial pain syndrome/myofascial trigger point assessment.

The impact of internet addiction on depression, physical activity level and trigger point sensitivity in Turkish university students

BACKGROUND AND OBJECTIVES

Internet addiction (IA), defined as excessive, time consuming, uncontrollable use of the internet, has become a widespread problem. In this study, we investigated the impact of internet addiction on depression, physical activity level, and latent trigger point sensitivity in Turkish university students.

METHODS

A total of 215 university students (155 females and 60 males) who were between 18-25 years of age participated in the study. Using the Addiction Profile Index Internet Addiction Form (APIINT), we identified 51 people as non-internet-addicted (non-IA) (Group 1: 10 male/41 female) and 51 as internet-addicted (IA) (Group 2: 7 male/44 female). APIINT, International Physical Activity Questionnaire-Short-Form (IPAQ), Beck Depression Inventory (BDI), and Neck Disability Index (NDI) were administered to both groups, and the pressure-pain threshold (PPT) in upper/middle trapezius latent trigger points area was measured.

RESULTS

The internet addiction rate was 24.3% in our students. Compared with the non-IA group, the daily internet use time and BDI and NDI scores were higher (all p< 0.05), while the IPAQ walking (p< 0.01), IPAQ total (p< 0.05), and PPT values (p< 0.05) were lower in the IA group.

CONCLUSIONS

IA is a growing problem. This addiction may lead to musculoskeletal problems and can have consequences involving the level of physical activity, depression, and musculoskeletal disorders, particularly in the neck.

Influence of quantified dry cupping on soft tissue compliance in athletes with myofascial pain syndrome

PURPOSE

This study aimed to develop a quantitative dry cupping system that can monitor negative pressure attenuation and soft tissue pull-up during cupping to quantify soft tissue compliance.

METHODS

Baseball players with myofascial pain syndrome were recruited to validate the benefits of cupping therapy. Nine of 40 baseball players on the same team were diagnosed with trapezius myofascial pain syndrome; another nine players from the same team were recruited as controls. All participants received cupping with a negative pressure of 400 mmHg for 15 minutes each time, twice a week, for 4 weeks. Subjective perception was investigated using upper extremity function questionnaires, and soft tissue compliance was quantified objectively by the system.

RESULTS

During the 15-minute cupping procedure, pressure attenuation in the normal group was significantly greater than that in the myofascial group (p = 0.017). The soft tissue compliance in the normal group was significantly higher than that in the myofascial group (p = 0.050). Moreover, a 4-week cupping intervention resulted in an obvious increase in soft tissue lift in the myofascial pain group (p = 0.027), although there was no statistical difference in the improvement of soft tissue compliance. Shoulder (p = 0.023) and upper extremity function (p = 0.008) were significantly improved in both groups, but there was no significant difference between the two groups.

CONCLUSION

This quantitative cupping monitoring system could immediately assess tissue compliance and facilitate the improvement of soft tissues after cupping therapy. Hence, it can be used in athletes to improve their functional recovery and maintain soft tissues health during the off-season period.

Ashi Acupuncture Versus Local Anesthetic Trigger Point Injections in the Treatment of Abdominal Myofascial Pain Syndrome: A Randomized Clinical Trial

BACKGROUND

Chronic pelvic pain (CPP) is defined as recurrent or continuous pain in the lower abdomen or pelvis, non-menstrual or non-cyclic, lasting at least 6 months. There is strong evidence that up to 85% of patients with CPP have serious dysfunction of the musculoskeletal system, including abdominal myofascial syndrome (AMPS). AMPS is characterized as deep abdominal pain, originating from hyperirritable trigger points, usually located within a musculoskeletal range or its fascia of coating. In the literature, there are few studies that address AMPS.

OBJECTIVE

This study aimed to compare the responses of ashi acupuncture treatment and local anesthetic injection in the treatment of chronic pelvic pain secondary to abdominal myofascial pain syndrome in women.

STUDY DESIGN

Randomized controlled clinical trial.

SETTING

Tertiary University Hospital.

METHODS

Women with a clinical diagnosis of CPP secondary to AMPS were randomized and evaluated using instruments to assess clinical pain, namely, the visual analogue scale (VAS), numerical categorial scale (NCS), and the McGill Questionnaire, after receiving treatment with ashi acupuncture (group A, n = 16) or local anesthetic injections (group B, n = 19). They were reevaluated after one week and one, 3, and 6 months after each treatment, in addition to assessments of pain and adverse events performed during the sessions.

RESULTS

Ashi acupuncture and local anesthetic injections were both effective in reducing clinical pain assessed through the analyzed variables among study participants. There was no difference between the groups and there was a strong correlation between these pain assessment instruments.

LIMITATIONS

The absence of blinding to the different forms of treatment among the patients and the researcher directly involved in the treatment, the absence of a placebo group, the selective exclusion of women with comorbidities and other causes of CPP, and the difference between the number of sessions used for each technique.

CONCLUSION

Treatments with ashi acupuncture and local anesthetic injections were effective in reducing clinical pain in women with abdominal myofascial pain syndrome.

Alleviation of migraine symptoms by application of repetitive peripheral magnetic stimulation to myofascial trigger points of neck and shoulder muscles - A randomized trial

Migraine is a burdensome disease with an especially high prevalence in women between the age of 15 and 49 years. Non-pharmacological, non-invasive therapeutic methods to control symptoms are increasingly in demand to complement a multimodal intervention approach in migraine. Thirty-seven subjects (age: 25.0 ± 4.1 years; 36 females) diagnosed with high-frequency episodic migraine who presented at least one active myofascial trigger point (mTrP) in the trapezius muscles and at least one latent mTrP in the deltoid muscles bilaterally prospectively underwent six sessions of repetitive peripheral magnetic stimulation (rPMS) over two weeks. Patients were randomly assigned to receive rPMS applied to the mTrPs of the trapezius (n = 19) or deltoid muscles (n = 18). Whereas the trapezius muscle is supposed to be part of the trigemino-cervical complex (TCC) and, thus, involved in the pathophysiology of migraine, the deltoid muscle was not expected to interfere with the TCC and was therefore chosen as a control stimulation site. The headache calendar of the German Migraine and Headache Society (DMKG) as well as the Migraine Disability Assessment (MIDAS) questionnaire were used to evaluate stimulation-related effects. Frequency of headache days decreased significantly in both the trapezius and the deltoid group after six sessions of rPMS (trapezius group: p = 0.005; deltoid group: p = 0.003). The MIDAS score decreased significantly from 29 to 13 points (p = 0.0004) in the trapezius and from 31 to 15 points (p = 0.002) in the deltoid group. Thus, rPMS applied to mTrPs of neck and shoulder muscles offers a promising approach to alleviate headache frequency and symptom burden. Future clinical trials are needed to examine more profoundly these effects, preferably using a sham-controlled setting.

The prevalence of myofascial trigger points in hip and thigh areas in anterior knee pain patients

BACKGROUND

Anterior knee pain (AKP) is a widespread problem among young athletes and soldiers. There are many theories on the etiology of AKP but there is little reference to myofascial trigger points (MTrPs) as a possible contributor.

AIM

To evaluate the association between AKP and prevalence of active and latent MTrPs in the hip and thigh muscles in soldiers.

METHODS

A cross-sectional study was conducted in the Beer-Sheva military outpatient physical therapy clinic. Subjects were 42 men and 23 women referred for physical therapy, 33 with a diagnosis of AKP (cases) and 32 with upper limb complaints (without AKP, controls). All subjects underwent physical evaluation by an examiner blinded to their identity and medical condition. The following muscles were assessed bilaterally for active or latent MTrPs: rectus femoris (proximal), vastus medialis (middle and distal), vastus lateralis (middle and distal) and gluteus medius (anterior, posterior and distal).

RESULTS

In six out of eight areas, the cases had a higher prevalence of total active and latent MTrPs than the controls. When summarizing MTrPs by muscle, cases had significantly more MTrPs than controls in each muscle. The largest difference was found in vastus medialis and vastus lateralis; nearly half of the cases had MTrPs in these muscles.

CONCLUSIONS

Subjects with AKP have a greater prevalence of MTrPs in their hip and thigh muscles than controls, indicating an association between MTrPs and AKP. Further research is necessary to determine whether MTrPs are the cause or the consequence of AKP.

Myofascial trigger points in migraine and tension-type headache

BACKGROUND

A myofascial trigger point is defined as a hyperirritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band. It has been suggested that myofascial trigger points take part in chronic pain conditions including primary headache disorders. The aim of this narrative review is to present an overview of the current imaging modalities used for the detection of myofascial trigger points and to review studies of myofascial trigger points in migraine and tension-type headache.

FINDINGS

Different modalities have been used to assess myofascial trigger points including ultrasound, microdialysis, electromyography, infrared thermography, and magnetic resonance imaging. Ultrasound is the most promising of these modalities and may be used to identify MTrPs if specific methods are used, but there is no precise description of a gold standard using these techniques, and they have yet to be evaluated in headache patients. Active myofascial trigger points are prevalent in migraine patients. Manual palpation can trigger migraine attacks. All intervention studies aiming at trigger points are positive, but this needs to be further verified in placebo-controlled environments. These findings may imply a causal bottom-up association, but studies of migraine patients with comorbid fibromyalgia syndrome suggest otherwise. Whether myofascial trigger points contribute to an increased migraine burden in terms of frequency and intensity is unclear. Active myofascial trigger points are prevalent in tension-type headache coherent with the hypothesis that peripheral mechanisms are involved in the pathophysiology of this headache disorder. Active myofascial trigger points in pericranial muscles in tension-type headache patients are correlated with generalized lower pain pressure thresholds indicating they may contribute to a central sensitization. However, the number of active myofascial trigger points is higher in adults compared with adolescents regardless of no significant association with headache parameters. This suggests myofascial trigger points are accumulated over time as a consequence of TTH rather than contributing to the pathophysiology.

CONCLUSIONS

Myofascial trigger points are prevalent in both migraine and tension-type headache, but the role they play in the pathophysiology of each disorder and to which degree is unclarified. In the future, ultrasound elastography may be an acceptable diagnostic test.

Dry Needling on the Infraspinatus Latent and Active Myofascial Trigger Points in Older Adults With Nonspecific Shoulder Pain: A Randomized Clinical Trial

BACKGROUND AND PURPOSE

Shoulder pain is a prevalent condition in older adults. Some authors associate nonspecific shoulder pain with myofascial trigger points (MTrPs) in the infraspinatus muscle. Dry needling is recommended to relieve the MTrP pain of shoulders in the short term (<9 days). Active MTrPs dry needling improves shoulder pain and the irritability of the satellite MTrPs in the referred pain area. Nociceptive activity at a latent MTrP may influence motor activity and the sensitivity of MTrPs in distant muscles at a similar segmental level. Therefore, this study aimed to evaluate dry needling on 1 latent MTrP, in conjunction with 1 active MTrP, in the infraspinatus muscle of older adults with nonspecific shoulder pain.

METHODS

A single-center, randomized, single-blinded, controlled study (NCT02032602) was carried out. Sixty-six patients aged 65 years and older with trigger points in the ipsilateral infraspinatus of the painful shoulder were randomly assigned to (1) of (2) treatment groups. A session of dry needling on the infraspinatus was performed in (1) the most hyperalgesic active and latent MTrP or (2) only the most hyperalgesic active MTrP. The Numeric Rating Scale, the pressure pain threshold (primary outcome) on the anterior deltoid and extensor carpi radialis brevis latent MTrPs, and grip strength were assessed before, after, and 1 week after the intervention.

RESULTS

Statistically significant differences in the reduction of pain intensity (P ≤ .001; η = 0.159-0.269; d = 1.017-1.219) and the increase of pressure pain threshold (P < .001; η = 0.206-0.481; d = 0.870-1.924) were found for the (1) treatment group immediately and 1 week postintervention. Nevertheless, no statistical significant differences were found in grip strength (P >. 05; η = 0.006-0.033; d = 0.158-0.368).

CONCLUSIONS

One dry needling intervention of the latent MTrP associated with the key active MTrP of the infraspinatus reduces pain intensity and the irritability of the satellite MTrPs located in the referred pain area in the short term in older adults with nonspecific shoulder pain.

A critical overview of the current myofascial pain literature - April 2018

Twenty-four basic and clinical studies and case reports are included in this quarterly review of the myofascial pain literature. The majority of publications focus on invasive techniques, especially dry needling. We hope, that this not suggest that clinicians and researchers are slowly moving away from manual trigger point (TrP) approaches. While some physiotherapists have bought into the notion that hands-on approaches are a thing of the past, since "pain is in the brain" and "the issues are not in the tissues," there is also a body of research that aims to combine so-called top-down and bottom-up therapies. Combining manual therapy and dry needling with pain neuroscience education is likely the preferred method using a multimodal approach (Puentedura and Flynn, 2016; Lluch Girbes et al., 2015).

Effects of dry needling trigger point therapy in the shoulder region on patients with upper extremity pain and dysfunction: a systematic review with meta-analysis

QUESTION

What is the effectiveness and what are the adverse effects.

DESIGN

Systematic review with meta-analysis.

PARTICIPANTS

Patients with shoulder or upper extremity pain or dysfunction.

INTERVENTION

Trigger point dry needling (TDN) compared to control, another intervention or another needling technique.

OUTCOME MEASURES

Primary outcome measures included shoulder or upper limb pain, shoulder or upper limb dysfunction.

RESULTS

Eleven randomized trials involving 496 participants were appraised. There was very low evidence that trigger point dry needling of the shoulder region is effective for reducing pain and improving function in the short term. There is some evidence that needling both active and latent trigger points is more effective than needling an active trigger point alone for pain immediately and 1-week after treatment (SMD=-0.74, 95%CI=-1.2 to -0.3; and SMD=-1.0, 95%CI=-1.52 to -0.59).

CONCLUSION

There is very low evidence to support the use of TDN in the shoulder region for treating patients with upper extremity pain or dysfunction. Two studies reported adverse effects to TDN interventions. Most common adverse effects included bruising, bleeding, and pain during or after treatment. Future studies are likely to change the estimates of the effectiveness of TDN for patients with upper extremity pain or dysfunction.

PROSPERO

CRD42016045639.

The effects of dry needling and radial extracorporeal shockwave therapy on latent trigger point sensitivity in the quadriceps: A randomised control pilot study

OBJECTIVES

Latent myofascial trigger points (TrP) can alter joint kinematics, reduce strength and alter activation patterns, affecting athletic performance. TrP sensitivity can be measured with the pressure pain threshold (PPT). Dry needling (DN) has been used to treat latent TrPs, but may cause post-needling soreness. Radial extracorporeal shockwave therapy (rESWT) could be used as an alternative to DN during heavy training or competition.

METHODS

After baseline measures, 21 recreational athletes were split into three groups: DN, rESWT or control group, and were treated for three sessions in one week. Follow-up outcome sessions were conducted two to four and seven days after the last treatment. TrP sensitivity was measured using the PPT.

RESULTS

There was a groupXtime interaction for the PPT (p < 0.05). After a decrease in PPT during treating, there was a significant increase (p < 0.05) in PPT for the DN group (12.92%). The rESWT group also significantly (p < 0.05) increased (13.26%), but did not show any post-treatment soreness during the treatment phase. There was no difference in the PPT in the control group during any session.

CONCLUSION

DN is effective for increasing PPT of latent TrPs, but can be associated with post-treatment soreness. rESWT is as effective, but without the post-treatment soreness. Future studies should include treating multiple TrPs in the lower kinetic chain as well as measuring muscle activation and joint function. Furthermore, consideration for the current training load and up-coming competition is needed. Optimum timing and longer follow-up periods of such interventions should be explored.

LEVEL OF EVIDENCE

2b.

SUMMARY

Treating latent TrPs in the lower kinetic chain may improve muscle activation. Unlike DN, rESWT does not cause post- treatment soreness. Consideration of training load and up-coming competition is needed to deliver the optimum treatment strategy for athletes with latent TrPs.

A critical overview of the current myofascial pain literature - January 2018

The majority of papers included in the quarterly review discuss various aspects of dry needling (DN), which continues to be of interest to researchers and clinicians. A study by Liu et al. is the first paper to examine the effects of DN of acetylcholine, esterase and receptors. The study provides support for the integrated trigger point hypothesis and for DN. A paper by Hightower and colleagues found an intriguing link between low magnesium levels in the drink water supply, vitamin D, and myofascial pain, cancer, tendon ruptures, and colon polyps. Contributions originated in the Brazil, China, Germany, Iran, India, Poland, South Korea, Spain, Taiwan, Turkey, and the US.

The association of headache frequency with pain interference and the burden of disease is mediated by depression and sleep quality, but not anxiety, in chronic tension type headache

BACKGROUND

A better understanding of potential relationship between mood disorders, sleep quality, pain, and headache frequency may assist clinicians in determining optimal therapeutic programs. The aim of the current study was to analyze the effects of sleep quality, anxiety, depression on potential relationships between headache intensity, burden of headache, and headache frequency in chronic tension type headache (CTTH).

METHODS

One hundred and ninety-three individuals with CTTH participated. Headache features were collected with a 4-weeks headache diary. The Hospital Anxiety and Depression Scale was used for assessing anxiety and depression. Headache Disability Inventory evaluated the burden of headache. Pain interference was determined with the bodily pain domain (SF-36 questionnaire). Sleep quality was assessed with Pittsburgh Sleep Quality Index. Path analyses with maximum likelihood estimations were conducted to determine the direct and indirect effects of depression, anxiety, and sleep quality on the frequency of headaches.

RESULT

Two paths were observed: the first with depression and the second with sleep quality as mediators. Direct effects were noted from sleep quality, emotional burden of disease and pain interference on depression, and from depression to headache frequency. The first path showed indirect effects of depression from emotional burden and from sleep quality to headache frequency (first model R 2 = 0.12). Direct effects from the second path were from depression and pain interference on sleep quality and from sleep quality on headache frequency. Sleep quality indirectly mediated the effects of depression, emotional burden and pain interference on headache frequency (second model R 2 = 0.18).

CONCLUSIONS

Depression and sleep quality, but not anxiety, mediated the relationship between headache frequency and the emotional burden of disease and pain interference in CTTH.

Comparison of shoulder strength in males with and without myofascial trigger points in the upper trapezius

BACKGROUND

This study was conducted in order to compare the strength of scapular elevator and shoulder abductor with and without restricted scapular elevation between male subjects with and without myofascial trigger points in the upper trapezius.

METHODS

In total, 15 male subjects with myofascial trigger points, and 15age- and weight-matched male subjects without myofascial trigger points in the upper trapezius. Each subject was measured in the strength of maximum isometric scapular elevation and shoulder abduction with and without restricted scapular elevation. Maximum isometric contractions were measured using the Smart KEMA strength measurement system. Independent t-tests were used to compare shoulder strength values between the myofascial trigger points and non- myofascial trigger points groups.

FINDING

The results showed that shoulder abductor strength in the group with myofascial trigger points (5.64kgf) was significantly lower than in the group without myofascial trigger points (11.96kgf) when scapular elevation was restricted (p<0.05). However, there was no significant difference in the strength of the scapular elevator or shoulder abductor between groups (p>0.05).

INTERPRETATION

These findings suggest that decreased strength in the shoulder abductor with restricted scapular elevation should be considered in evaluating and treating individuals with myofascial trigger points of the upper trapezius.

Comparison of acute effects of superficial and deep dry needling into trigger points of suboccipital and upper trapezius muscles in patients with cervicogenic headache

OBJECTIVE

The purpose of this study was to compare the acute effects of superficial and deep dry needling into trigger points of suboccipital and upper trapezius muscles in patients with cervicogenic headache.

METHODS

Thirty participants (8 men, 22 women) aged 19-60 years (mean age ± SD, 39 ± 10 y) with a clinical diagnosis of cervicogenic headache were randomly divided into superficial and deep groups. Headache index, trigger points tenderness, cervical range of motion (CROM), functional rating index was assessed at baseline, immediate and 1 week after the treatment.

RESULTS

Two approaches of dry needling showed reduction in headache index and trigger points tenderness. Deep dry needling showed greater improvement of cervical range of motion (p < 0.001) and functional rating index (p < 0.01).

CONCLUSION

The application of dry needling into trigger points of suboccipital and upper trapezius muscles induces significant improvement of headache index, trigger points tenderness, functional rating index and range of motion in patients with cervicogenic headache. Deep dry needling had greater effects on CROM and function.

Therapeutic effects of dry needling in patients with upper trapezius myofascial trigger points

BACKGROUND

Active myofascial trigger points (MTrPs) are major pain generators in myofascial pain syndrome. Dry needling (DN) is an effective method for the treatment of MTrPs.

OBJECTIVE

To assess the immediate neurophysiological and clinical effects of DN in patients with upper trapezius MTrPs.

METHODS

This was a prospective, clinical trial study of 20 patients with upper trapezius MTrPs and 20 healthy volunteers (matched for height, weight, body mass index and age), all of whom received one session of DN. Primary outcome measures were neuromuscular junction response (NMJR) and sympathetic skin response (SSR). Secondary outcomes were pain intensity (PI) and pressure pain threshold (PPT). Data were collected at baseline and immediately post-intervention.

RESULTS

At baseline, SSR amplitude was higher in patients versus healthy volunteers (p<0.003). With respect to NMJR, a clinically abnormal increment and normal reduction was observed in patients and healthy volunteers, respectively. Moreover, PPT of patients was less than healthy volunteers (p<0.0001). After DN, SSR amplitude decreased significantly in patients (p<0.01), but did not change in healthy volunteers. A clinically important reduction in the NMJR of patients and increment in healthy volunteers was demonstrated after DN. PPT increased after DN in patients, but decreased in healthy volunteers (p<0.0001). PI improved after DN in patients (p<0.001).

CONCLUSIONS

The results of this study showed that one session of DN targeting active MTrPs appears to reduce hyperactivity of the sympathetic nervous system and irritability of the motor endplate. DN seems effective at improving symptoms and deactivating active MTrPs, although further research is needed.

TRIAL REGISTRATION NUMBER

IRCT20130316128.

Neurophysiological and clinical effects of dry needling in patients with upper trapezius myofascial trigger points

INTRODUCTION

Dry needling (DN) is a widely used in treatment of myofascial trigger points (MTrPs). The purpose of this pretest-posttest clinical trial was to investigate the neurophysiological and clinical effects of DN in patients with MTrPs.

METHODS

A sample of 20 patients (3 man, 17 women; mean age 31.7 ± 10.8) with upper trapezius MTrPs received one session of deep DN. The outcomes of neuromuscular junction response (NMJR), sympathetic skin response (SSR), pain intensity (PI) and pressure pain threshold (PPT) were measured at baseline and immediately after DN.

RESULTS

There were significant improvements in SSR latency and amplitude, pain, and PPT after DN. The NMJR decreased and returned to normal after DN.

CONCLUSIONS

A single session of DN to the active upper trapezius MTrP was effective in improving pain, PPT, NMJR, and SSR in patients with myofascial trigger points. Further studies are needed.

Presence of Latent Myofascial Trigger Points and Determination of Pressure Pain Thresholds of the Shoulder Girdle in Healthy Children and Young Adults: A Cross-sectional Study

OBJECTIVE

The primary objective of this study was to compare the number of myofascial trigger points (MTPs) and the pressure pain thresholds (PPTs) in the shoulder girdle, on the dominant and nondominant sides, between healthy children and adults. The secondary aim was to assess the correlations between the number of MTPs and the PPTs in these populations.

METHODS

A cross-sectional study was performed. Thirty-five children (aged 9.1 ± 1.7 years) and 35 adults (aged 23.4 ± 3.4 years) with no history of shoulder or cervical pathology were included. All participants were examined for MTPs in the shoulder muscles and assessed for PPTs in the neck, shoulder, and tibialis anterior. Parametric and nonparametric tests, effect sizes, and odds ratios were used to determine the differences between groups and sides. Spearman's σ test was used to assess correlations between latent MTPs (LTPs) and PPTs in each group.

RESULTS

Children had fewer LTPs than adults did (P = .03). The upper trapezius was the muscle with the largest number of LTPs, affecting 13 adults on the dominant side. Children had lower PPTs compared with adults (P < .05). Correlations between the number of LTPs (on both sides and in total) and PPTs were observed only in adults.

CONCLUSIONS

Healthy children have fewer LTPs and lower PPTs in the shoulder girdle than healthy adults. A relationship was observed between sensitivity to pressure and the presence of LTPs in adults, in whom lower PPT was associated with more LTPs. This relationship was not detected in children.

Myofascial pain of the head and neck among Croatian war veterans treated for depression and posttraumatic stress disorder

BACKGROUND

During the Croatian War of Independence, 1991-1995, Croatian soldiers were exposed to traumatic and stressful events. Certain number of soldiers who took part in the war, developed depression and posttraumatic stress disorder (PTSD). Stress is one of the etiological factors in the development of myofascial pain (MPS), although the mechanism of these processes is not entirely understood. The aims of this study were to determine the frequency of myofascial pain among Croatian war veterans with depression and PTSD, association between MPS and severity of depression, to describe the most common locations of trigger points in the region of head and neck, and to find out if there is any association in frequency between MPS and endotracheal intubation.

SUBJECTS AND METHODS

A total of 101 Croatian war veterans suffering from PTSD and depression participated in the current study. Diagnosis of myofascial pain was based on detailed anamnestic history and careful clinical examination.

RESULTS

Our findings showed a high rate of myofascial pain among Croatian war veterans, with occipital region and right temporal region as the most common places of trigger points. Higher severity of depression was accompanied by a higher percentage of subjects with MPS. Finally, there was no significant association between endotracheal intubation and development of MPS among the war veterans.

CONCLUSIONS

It can be concluded that the rate of myofascial pain among Croatian war veterans is high and therefore it must be considered in patients with depression and PTSD. Moreover, the severity of depressive symptomatology seems to be related to the presence of myofascial pain.

Additional Effects of a Physical Therapy Protocol on Headache Frequency, Pressure Pain Threshold, and Improvement Perception in Patients With Migraine and Associated Neck Pain: A Randomized Controlled Trial

OBJECTIVE

To evaluate the additional effect provided by physical therapy in migraine treatment.

DESIGN

Randomized controlled trial.

SETTING

Tertiary university-based hospital.

PARTICIPANTS

Among the 300 patients approached, 50 women (age range, 18-55y) diagnosed with migraine were randomized into 2 groups: a control group (n=25) and a physiotherapy plus medication group (n=25) (N=50).

INTERVENTIONS

Both groups received medication for migraine treatment. Additionally, physiotherapy plus medication patients received 8 sessions of physical therapy over 4 weeks, comprised mainly of manual therapy and stretching maneuvers lasting 50 minutes.

MAIN OUTCOME MEASURES

A blinded examiner assessed the clinical outcomes of headache frequency, intensity, and self-perception of global change and physical outcomes of pressure pain threshold and cervical range of motion. Data were recorded at baseline, posttreatment, and 1-month follow-up.

RESULTS

Twenty-three patients experienced side effects from the medication. Both groups reported a significantly reduced frequency of headaches; however, no differences were observed between groups (physiotherapy plus medication patients showed an additional 18% improvement at posttreatment and 12% improvement at follow-up compared with control patients, P>.05). The reduction observed in the physiotherapy plus medication patients was clinically relevant at posttreatment, whereas clinical relevance for control patients was demonstrated only at follow-up. For pain intensity, physiotherapy plus medication patients showed statistical evidence and clinical relevance with reduction posttreatment (P<.05). In addition, they showed better self-perception of global change than control patients (P<.05). The cervical muscle pressure pain threshold increased significantly in the physiotherapy plus medication patients and decreased in the control patients, but statistical differences between groups were observed only in the temporal area (P<.05). No differences were observed between groups regarding cervical range of motion.

CONCLUSIONS

We cannot assume that physical therapy promotes additional improvement in migraine treatment; however, it can increase the cervical pressure pain threshold, anticipate clinically relevant changes, and enhance patient satisfaction.

Efficacy and Safety of Single Botulinum Toxin Type A (Botox®) Injection for Relief of Upper Trapezius Myofascial Trigger Point: A Randomized, Double-Blind, Placebo-Controlled Study

OBJECTIVE

Botulinum toxin injection has been applied for pain relief in various chronic pain syndromes. Recently, systematic review studies reported inconclusive effects of Botulinum toxin in myofascial pain management. The present study aimed to demonstrate the efficacy and safety of Botulinum toxin type A (BTxA) (Botox®) injection for pain reduction in myofascial trigger point (MTrP) of the upper trapezius muscle.

MATERIAL AND METHOD

Thirty-three patients with 48 MTrP on the upper trapezius muscles over three months with moderate to severe pain intensity diagnosed at physical medicine and rehabilitation outpatient department were recruited between December 2011 and March 2012. Eligible patients were blinded and randomly injected with single 0.2 ml (20 IU) of BTxA for 24 MTrP and 0.2 ml of 0.9% NaCl solution for 24 MTrP at the most tender trigger point on the upper trapezius muscle. All patients were advised for stretching exercise and ergonomic adaptation throughout the study. At 3- and 6-week after injections, visual analogue scale (VAS), the pressure pain threshold (PPT), and reported adverse effects were measured.

RESULTS

Both BTxA and control groups demonstrated statistically significant differences in VAS reduction and increased PPT after 3 weeks and 6 weeks compared with before treatment. There were no statistically significant differences in VAS reduction from baseline between the two groups at 3- and 6-week after treatment. A statistically significant difference in improvement of PPT from baseline and 6-week after BTxA injection compared with 0.9% NaCl group was shown (1.0 ± 0.9 and 0.5 ± 0.7, p = 0.036). There was mild degree side-effects that spontaneous resolved within one week in both groups without significant difference in percentage. No severe adverse effects were reported during the study.

CONCLUSION

The efficacy in VAS reduction of a single 20 IU of Botulinum toxin type A (Botox®) injection was not different from 0.9% NaCl for myofascial trigger point at the upper trapezius muscle. However Botulinum toxin type A (Botox®) showed statistically significant more increased in pressure pain threshold at 6-week after injection without severe adverse effects.

Myofascial Trigger Points Then and Now: A Historical and Scientific Perspective

The intent of this article is to discuss the evolving role of the myofascial trigger point (MTrP) in myofascial pain syndrome (MPS) from both a historical and scientific perspective. MTrPs are hard, discrete, palpable nodules in a taut band of skeletal muscle that may be spontaneously painful (i.e., active) or painful only on compression (i.e., latent). MPS is a term used to describe a pain condition that can be acute or, more commonly, chronic and involves the muscle and its surrounding connective tissue (e.g. fascia). According to Travell and Simons, MTrPs are central to the syndrome-but are they necessary? Although the clinical study of muscle pain and MTrPs has proliferated over the past two centuries, the scientific literature often seems disjointed and confusing. Unfortunately, much of the terminology, theories, concepts, and diagnostic criteria are inconsistent, incomplete, or controversial. To address these deficiencies, investigators have recently applied clinical, imaging (of skeletal muscle and brain), and biochemical analyses to systematically and objectively study the MTrP and its role in MPS. Data suggest that the soft tissue milieu around the MTrP, neurogenic inflammation, sensitization, and limbic system dysfunction may all play a role in the initiation, amplification, and perpetuation of MPS. The authors chronicle the advances that have led to the current understanding of MTrP pathophysiology and its relationship to MPS, and review the contributions of clinicians and researchers who have influenced and expanded our contemporary level of clinical knowledge and practice.

[Myofascial pain syndrome treated with sparrow-pecking moxibustion at trigger points: a randomized controlled trial]

OBJECTIVE

To compare the efficacy difference in treatment of myofasical pain syndrome between sparrow-pecking moxibustion and acupuncture at trigger points so as to provide the reference of the effective therapeutic method for myofascial pain syndrome.

METHODS

Ninety patients were randomized into a sparrow-pecking moxibustion group and an acupuncture group, 45 cases in each one. The trigger points were selected in pain areas in the two groups. In the sparrow-pecking moxibustion group, the sparrow-pecking moxibustion was applied, 30 min in each time. In the acupuncture group, the filiform needles were inserted obliquely at 45 degrees and retained for 40 min in each treatment. The treatment was given once a day and 10 treatments made one session in the two groups. The short-form McGill pain questionnaire was used as the observation index, and the changes in pain rating index (PRI), present pain intensity (PPI) and visual analogue scale (VAS) before and after treatment were used for efficacy assessment.

RESULTS

The results of PRI, PPI and VAS after treatment were reduced apparently as compared with those before treatment in the sparrow-pecking moxibustion group and the acupuncture group (all P<0.001). The differences in PRI, PPI and VAS after treatment were not significant in comparison of the two groups (both P>0.05). The curative and remarkably effective rate was 80.0% (36/45) in the sparrow-pecking moxibustion group, which was better than 40.0% (18/45, P<0.001) in the acupuncture group.

CONCLUSION

Sparrow-pecking moxibustion at trigger points achieves the superior efficacy on myofascial pain syndrome as compared with acupuncture at trigger points. This therapy is simpler in operation additionally.

Occipital nerve stimulation for chronic migraine

Occipital nerve stimulation may be effective in treating chronic migraine. Six studies, including three double-blind studies, were performed, with five showing evidence of benefit. However, of the three randomized, controlled trials, none has met a primary endpoint successfully. A separate study suggested a benefit for combined supraorbital and greater occipital nerve stimulation.

[Clinical observation on therapeutic effect of cupping combined with acupuncture stimulation at trigger points for lumbar myofascial pain syndrome]

OBJECTIVE

To observe the clinical effect of cupping combined with acupuncture stimulation of trigger points on lumbar myofascial pain syndrome (MPS).

METHODS

Sixty MPS patients were randomly divided into acupuncture + TDP group (n = 30), and cupping + acupuncture group (n = 30). Patients in the acupuncture + TDP group were treated by acupuncture stimulation of trigger points and local TDP irradiation, and patients of the cupping + acupuncture group treated by intensive cupping applied to the myofascial band and acupuncture stimulation of the locus according to the position of muscular tension band. The therapeutic effects were assessed according to the score of the McGill pain questionnaire composing of pain rating index (PRI), visual analogue scale (VAS) and present pain intensity (PPI) before, immediately and 1 month after the treatment.

RESULTS

After the treatment, the total effective rates of the acupuncture+ TDP and cupping + acupuncture groups were 83.3% (25/30) and 96.6% (29/30), respectively, without significant difference between the two groups (P > 0.05). One month's follow-up showed that the total effective rates of the acupuncture + TDP and cupping + acupuncture groups were 40.0% and 90.0% respectively, and the latter group was significantly better than the acupuncture + TDP group in the therapeutic effect (P < 0.05). The scores of PRI, VAS, PPI after the treatment were markedly decreased in both groups (P < 0.05). One month later, the scores of PRI, VAS and PPI in the cupping + acupuncture group were obviously lower than those of the acupuncture group (P < 0.05).

CONCLUSION

Both acupuncture stimulation of trigger points plus TDP and cupping plus acupuncture can effectively relieve pain in MPS patients, while the therapeutic effect of cupping plus acupuncture treatment lasts longer analgesic effect.

Clinical implication of latent myofascial trigger point

Myofascial trigger points (MTrPs) are hyperirritable points located within a taut band of skeletal muscle or fascia, which cause referred pain, local tenderness and autonomic changes when compressed. There are fundamental differences between the effects produced by the two basic types of MTrPs (active and latent). Active trigger points (ATrPs) usually produce referred pain and tenderness. In contrast, latent trigger points (LTrPs) are foci of hyperirritability in a taut band of muscle, which are clinically associated with a local twitch response, tenderness and/or referred pain upon manual examination. LTrPs may be found in many pain-free skeletal muscles and may be "activated" and converted to ATrPs by continuous detrimental stimuli. ATrPs can be inactivated by different treatment strategies; however, they never fully disappear but rather convert to the latent form. Therefore, the diagnosis and treatment of LTrPs is important. This review highlights the clinical implication of LTrPs.

Sono-myography and sono-myoelastography of the tender points of women with fibromyalgia

Sono-myography and sono-myoelastography have been found useful in the investigation of myofascial trigger points. The objective of this study was to use the same techniques to investigate the morphology, stiffness and blood flow of tender points in women with fibromyalgia and to compare the results with those for samples from healthy patients. Algometry tests indicated significant differences between groups (p < 0.001). Elliptical and hypoechoic areas were observed in the ultrasound images of the upper trapezius in both groups. No differences between groups were found in the number of hypoechoic areas (p = 0.167, t = 1.008); blood flow also did not differ between the groups. Larger hypoechoic areas were found in the fibromyalgia group (p = 0.139, t = 1.317). Sono-myoelastography did not reveal greater stiffness in these areas compared with the rest of the muscle. These results lead us to believe that sono-myoelastography and sono-myography, used in the diagnosis of myofascial trigger points, may not be able to discriminate tender points.

[Comparative study on effect of acupuncture and lidocaine block for lumbar myofascial pain syndrome]

OBJECTIVE

To observe the clinical efficacy of acupuncture at Jiaji (EX-B 2) points mainly for lumbar myofascial pain syndrome (MPS).

METHODS

Sixty-six cases of MPS were randomized into an acupuncture group and a lidocaine group, 33 cases in each group. The acupuncture group was treated with acupuncture at Jiaji (EX-B 2) points combined with needling local myofascial trigger points (MTrP), and the lidocaine group was treated with local block at trigger points with lidocaine injection. The treatment was given once every 2 days. After three and five times of the treatment, the simplified McGill scale, Oswestry disability index (ODI) and pressure-pain threshold were assessed to compare the therapeutic effects between the two groups.

RESULTS

After treatment, the scores of simplified McGill and ODI of two groups were obviously reduced while the score of pressure-pain threshold was obviously increased (all P < 0.01). After three and five times of the treatment, there were no significant differences in above scores between the two groups (all P > 0.05).

CONCLUSION

Acupuncture at Jiaji (EX-B 2) points combined with needling MTrP is an effective and safe therapy for lumbar MPS, the therapeutic effect is equal to lidocaine block.

Myofascial trigger point pain

Myofascial trigger point pain is an extremely prevalent cause of persistent pain disorders in all parts of the body, not just the head, neck, and face. Features include deep aching pain in any structure, referred from focally tender points in taut bands of skeletal muscle (the trigger points). Diagnosis depends on accurate palpation with 2-4 kg/cm2 of pressure for 10 to 20 seconds over the suspected trigger point to allow the referred pain pattern to develop. In the head and neck region, cervical muscle trigger points (key trigger points) often incite and perpetuate trigger points (satellite trigger points) and referred pain from masticatory muscles. Management requires identification and control of as many perpetuating factors as possible (posture, body mechanics, psychological stress or depression, poor sleep or nutrition). Trigger point therapies such as spray and stretch or trigger point injections are best used as adjunctive therapy.

Efficacy of myofascial trigger point deactivation for tinnitus control

Chronic pain in areas surrounding the ear may influence tinnitus.

Objective

To investigate the efficacy of myofascial trigger point deactivation for the relief of tinnitus.

Method

A double-blind randomized clinical trial enrolled 71 patients with tinnitus and myofascial pain syndrome. The experimental group (n = 37) underwent 10 sessions of myofascial trigger point deactivation and the control group (n = 34), 10 sessions with sham deactivation.

Results

Treatment of the experimental group was effective for tinnitus relief (p < 0.001). Pain and tinnitus relieves were associated (p = 0.013), so were the ear with worst tinnitus and the side of the body with more pain (p < 0.001). The presence of temporary tinnitus modulation (increase or decrease) upon initial muscle palpation was frequent in both groups, but its temporary decrease was related to the persistent relief at the end of treatment (p = 0.002).

Conclusion

Besides medical and audiological investigation, patients with tinnitus should also be checked for: 1) presence of myofascial pain surrounding the ear; 2) laterality between both symptoms; 3) initial decrease of tinnitus during muscle palpation. Treating this specific subgroup of tinnitus patients with myofascial trigger point release may provide better results than others described so far.

Complementary treatment in fibromyalgia: combination of somatic and abdominal acupuncture

Fibromyalgia is a complex syndrome characterised by widespread pain associated with a variety of other signs and symptoms. The emerging consensus indicates that the best approach to treatment involves the combination of pharmacological and non-pharmacological interventions. Since acupuncture is a tool of traditional Chinese medicine increasingly used as an alternative or complementary therapy for the treatment of pain, the present study aimed to combine two different acupunctural methods (the somatic and abdominal one) in the treatment of 30 consecutive female FM patients and to evaluate the reduction of pain and the well-being state. The results showed a statistically significant reduction of the number of tender points and of pain. Moreover we observed a statistically significant reduction of FIQ, FAS, HAQ, disease activity VAS, ZSAS, ZSDS at the end of the treatment. In conclusion, these data suggest that the combination of two types of acupuncture could be a useful complementary treatment in FM patients, not only to control pain but also to improve associated symptoms and quality of life. As a result, acupuncture could be very useful to relieve pain in a multidisciplinary setting.

Etiology of myofascial trigger points

Myofascial pain syndrome (MPS) is described as the sensory, motor, and autonomic symptoms caused by myofascial trigger points (TrPs). Knowing the potential causes of TrPs is important to prevent their development and recurrence, but also to inactivate and eliminate existing TrPs. There is general agreement that muscle overuse or direct trauma to the muscle can lead to the development of TrPs. Muscle overload is hypothesized to be the result of sustained or repetitive low-level muscle contractions, eccentric muscle contractions, and maximal or submaximal concentric muscle contractions. TrPs may develop during occupational, recreational, or sports activities when muscle use exceeds muscle capacity and normal recovery is disturbed.

[Myofascial trigger points, pain, disability and quality of sleep in patients with chronic tension-type headache: a pilot study]

INTRODUCTION. The referred pain induced by myofascial trigger points (MTP) and sleep disorders can be factors that contribute to chronic tension-type headache. AIM. To determine the relationship between MTP, intensity of pain, disability and quality of sleep in people with chronic tension-type headache. SUBJECTS AND METHODS. Participants in the study consisted of 16 patients with chronic tension-type headache and 15 healthy controls. A visual analogue scale was used to measure the intensity of the pain, and the neck disability questionnaire and the Pittsburgh (quality of sleep) questionnaire were also employed. MTP were explored in the temporal, masseter, upper trapezius, suboccipital, sternocleidomastoid, splenius capitis, semispinalis capitis and anterior digastric muscles by a blind evaluator. RESULTS. The subjects with chronic tension-type headache had greater cervical disability (p < 0.001) than the controls, whereas the quality of sleep showed a tendency (p = 0.092). A positive correlation was found between the worst pain last week with the Pittsburgh questionnaire (r = 0.631; p = 0.009) and disability (r = 0.521; p = 0.046), as well as a positive correlation between disability and quality of sleep (r = 0.815; p < 0.001). The patients with headache displayed a higher number of MTP than the healthy controls (p < 0.001), the presence of active MTP being found exclusively in the patients. No association was found between the number of MTP and intensity of pain, disability or quality of sleep. CONCLUSIONS. Quality of sleep and active MTP can be different factors contributing to chronic tension-type headache. Nevertheless, the presence of MTP could also be an epiphenomenon of the pain.

[Progress of research on acupuncture at trigger point for myofascial pain syndrome]

To review the literature of acupuncture at trigger point for myofascial pain syndrome from the main selected points (trigger point), the mechanism of Chinese medicine and modern research and its clinical application. The results show that acupuncture at trigger point has significant effect on the myofascial pain syndrome, which could be influenced by the type of needle, manipulation, insertion angle and depth of the needles. However, the involved studies at present are still far from enough and lack of systematic study with multivariate analysis, it is needed to be improved that some problems about the clinical diagnosis and basic research.

Active myofascial trigger points might be more frequent in patients with cervical radiculopathy

BACKGROUND

Myofascial trigger points (MTrPs) are commonly observed in the neck, parascapular region, and upper back muscles of patients with cervical pathology.

AIM

To assess the frequency of latent and active myofascial trigger point (aMTrP) in the neck and upper back muscles in patients with cervical radiculopathy and healthy subjects.

DESIGN

Controlled clinical trials.

SETTING

Outpatients and controls.

POPULATION

Two hundred and forty four patients and 122 controls

METHODS

The patients clinically diagnosed as cervical radiculopathy with positive Spurling's test and confirmed by MRI, were enrolled in this study. All subjects were examined for active and latent MTrP. In patients with cervical radiculopathy, an aMTrP was distinguished from a latent one when the referred pain elicited by exploration of the MTrP is recognized as familiar.

RESULTS

The patients comprised of 128 female (52.5%) and 116 male (47.5%) patients. Mean age was 44.58(20-65 years). In 125 (51.2%) of patients with cervical radiculopathy were found an aMTrP at least one muscle from upper trapezius, multifidus, splenius capitis, levator scapulae, rhomboid major, minor and deep paraspinal muscles. Number and distribution of MTrPs in patients with 244 cervical radiculopathy and in healthy controls. aMTrPs were detected most common in levator scapula (16.3%), splenius capitis (14.7%), rhomboid minor (14.3%), upper part of trapezius (13.5%), rhomboid major (10.2%) and multifidus (8.6%) muscles. Patients with cervical radiculopathy showed latent MTrP in levator scapula (27%), splenius capitis (16.8%), rhomboid minor (24.6%), upper part of trapezius (33.2%), rhomboid major (9%) and multifidus (8.2%) muscles. There was significant difference in terms of distribution of active and latent MTrPs in patients with cervical radiculopathy (P=0.019). Number of latent MTrPs in upper trapezius muscles in patients with cervical radiculopathy was more than the expected distribution. None of the subjects of control group had aMTrP. However, healthy controls showed latent MTrP in levator scapula (33.6%), splenius capitis (16.4%), rhomboid minor (21.3%), upper part of trapezius (40.2%), rhomboid major (6.5%) and multifidus (17.2%) muscles. There was no significant difference in terms of distribution of latent MTrPs between cervical radiculopathy and control groups (P=0.249). The frequency of aMTrP was found to be significantly higher in CDH with median localization as compared to posterolateral herniations (P=0.041). After conservative treatment for two weeks, number of patients with active MTrP in cervical radiculopathy were decreased about 50%.

CONCLUSION

Cervical root compression would be considered as the starting or maintaining factor of aMTrP.

CLINICAL REHABILITATION IMPACT

The treatment of cervical radiculopathy might be facilitated the improving in aMTrPs located in aforementioned muscles.

[Clinical efficacy observation on primary trigeminal neuralgia treated with joint needling method at the trigger point]

OBJECTIVE

To observe the clinical efficacy on primary trigeminal neuralgia treated with joint needling method at the trigger point.

METHODS

One hundred and three cases of primary trigeminal neuralgia were divided into a joint needling group (53 cases) and a conventional needling group (50 cases) according to the visit sequence. In the joint needling group, the joint needling method was used at the trigger point in the mandibular joint [the positive point near to Xiaguan (ST 7)]; the conventional needling was used at Hegu (LI 4), Waiguan (TE 5), Taichong (LR 3) and Neiting (ST 44). In the conventional needling group, Xiaguan (ST 7) and Fengchi (GB 20) were used and the supplementary acupoints were selected according to the involved branches of trigeminal nerve. The conventional needling method was used. The Visual Analogue Scale (VAS) and the score of trigeminal neuralgia were adopted to assess the pain severity and the comprehensive symptoms before treatment and after the 1st and 2nd sessions of treatment separately. The efficacy was assessed.

RESULTS

After the 1st and 2nd sessions of treatment, VAS score and the comprehensive symptom score were reduced obviously as compared with those before treatment in either group (P < 0.05, P < 0.01). The score reducing in the joint needling group was much superior to that in the conventional needling group (both P < 0.05). The total effective rate was 90.6% (48/53) and 72. 0% (36/50) in the joint needling group and the conventional needling group respectively. The effect in the joint needling group was better than that in the conventional needling group (P < 0.05).

CONCLUSION

The joint needling method at the trigger point achieves the significant efficacy on primary trigeminal neuralgia, which is superior to that with the conventional needling method.

[Modern medical explanation on Ashi points]

According to the comparison between Ashi points and trigger points, a modern medical explanation that trigger points could be considered as a special Ashi points was put forward, and a further investigation on the enlightenment of theory and practice of trigger points to the pathological specificity, positioning and the intervention methods of trigger points was as follows: Ashi points could be central trigger points, whose pathology is degeneration and contracture of sarcomere; it is not always in the area of pain, while the signs of pain may be helpful for its stereotaxic positioning; the intervention methods of Ashi and trigger points can be learned from each other. This is a new angle of view on Ashi points, which has contributed to the exploration and improvement of its theory and practice.

Objective sonographic measures for characterizing myofascial trigger points associated with cervical pain

OBJECTIVES

The purpose of this study was to determine whether the physical properties and vascular environment of active myofascial trigger points associated with acute spontaneous cervical pain, asymptomatic latent trigger points, and palpably normal muscle differ in terms of the trigger point area, pulsatility index, and resistivity index, as measured by sonoelastography and Doppler imaging.

METHODS

Sonoelastography was performed with an external 92-Hz vibration in the upper trapezius muscles in patients with acute cervical pain and at least 1 palpable trigger point (n = 44). The area of reduced vibration amplitude was measured as an estimate of the size of the stiff myofascial trigger points. Patients also underwent triplex Doppler imaging of the same region to analyze blood flow waveforms and calculate the pulsatility index of blood flow in vessels at or near the trigger points.

RESULTS

On sonoelastography, active sites (spontaneously painful with palpable myofascial trigger points) had larger trigger points (mean ± SD, 0.57 ± 0.20 cm(2)) compared to latent sites (palpable trigger points painful on palpation; 0.36 ± 0.16 cm(2)) and palpably normal sites (0.17 ± 0.22 cm(2); P < .01). Analysis of receiver operating characteristic curves showed that area measurements could robustly distinguish between active, latent, and normal sites (areas under the curve, 0.9 for active versus latent, 0.8 for active versus normal, and 0.8 for latent versus normal, respectively). Doppler spectral waveform data showed that vessels near active sites had a significantly higher pulsatility index (median, 8.3) compared to normal sites (median, 3.0; P < .05).

CONCLUSIONS

The results presented in this study show that myofascial trigger points may be classified by area using sonoelastography. Furthermore, monitoring the trigger point area and pulsatility index may be useful in evaluating the natural history of myofascial pain syndrome.

Involvement of NGF in the rat model of persistent muscle pain associated with taut band

Myofascial pain syndrome (MPS) is an important clinical condition characterized by chronic muscle pain and a myofascial trigger point (MTrP) located in a taut band (TB). However, its pathogenic mechanism is still unclear. We developed an animal model relevant to conditions of MPS, and analyzed the mechanism of the muscle pain in this model. We applied eccentric contraction (EC) to a rat's gastrocnemius muscle (GM) for 2 weeks, and examined the mechanical withdrawal thresholds, histological changes, and expressions and contents of nerve growth factor (NGF). The mechanical withdrawal threshold decreased significantly at the next day of first EC and continued up to 9 days after EC. TBs were palpable at 3 to 8 days after initiation of EC. In EC animals, necrotic and regenerating muscle cells were found significantly more than in control animals. In EC animals, NGF expressions in regenerating muscle cells and NGF contents of GM were significantly higher than control animals. Administration of NGF receptor (TrkA) inhibitor K252a showed significant suppression of mechanical hyperalgesia in EC animals. Repeated EC induced persistent mechanical muscle hyperalgesia associated with TB. NGF expressed in regenerating muscle cells may have an important role in persistent mechanical muscle hyperalgesia which might be relevant to pathogenesis of MPS.

PERSPECTIVE

The present study shows that NGF expressed in regenerating muscle cells is involved in persistent muscular mechanical hyperalgesia. NGF-TrkA signaling in primary muscle afferent neurons may be one of the most important and promising targets for MPS.

Diagnosis and management of somatosensory tinnitus: review article

Tinnitus is the perception of sound in the absence of an acoustic external stimulus. It affects 10-17% of the world's population and it a complex symptom with multiple causes, which is influenced by pathways other than the auditory one. Recently, it has been observed that tinnitus may be provoked or modulated by stimulation arising from the somatosensorial system, as well as from the somatomotor and visual-motor systems. This specific subgroup -somatosensory tinnitus - is present in 65% of cases, even though it tends to be underdiagnosed. As a consequence, it is necessary to establish evaluation protocols and specific treatments focusing on both the auditory pathway and the musculoskeletal system.